(NewsNation) — A neighbor of the 18-year-old responsible for the fatal mass shooting at a Uvalde, Texas elementary school said the man was known to be bullied by teens and fought with his grandmother.

Salvador Ramos killed 19 children and two adults when he opened fire at Robb Elementary School. An 8-year-old boy, a 10-year-old girl, and two teachers were among those killed. Seventeen others were injured and continue to receive treatment Wednesday morning, according to the Texas Department of Public Safety.

Ramos was shot and killed by a Border Patrol agent who was responding to the active shooter scene Tuesday.

The shooter had recently moved in with his grandparents, said Joseph Moreno, who lives next door to the shooter’s grandparents.

“The grandson was staying there with them because he got into a fight with his mom,” he said.

Investigators have said that the gunman shot his grandmother before going to the school. She remained in serious condition Wednesday afternoon.

“She was a wonderful person. Hopefully, she’ll make it out OK,” Moreno said about the grandmother.

Ramos was often bullied by other teens, Moreno said.

“They would make fun of him because of the way he dressed,” he said. “He has a lisp, and they would make fun of him.”

When asked why he thought Ramos reportedly committed the mass shooting, Moreno said Ramos “was just mad at the world. They wouldn’t accept him the way he was.”

In the small community of Uvalde, Moreno, like many others, had deep connections with Robb Elementary School. His daughter is the principal and his granddaughter “works there as a parent liaison.”

FBI agents were speaking with the gunman’s neighbors, including Moreno, Tuesday and seeking information and surveillance footage.

If you or someone you know is thinking of harming themself, the National Suicide Prevention Lifeline provides free support at 1-800-273-8255. Starting on July 16, 2022, U.S. residents can also be connected to the Lifeline by dialing 988. For more about risk factors and warning signs, visit the organization’s official website.